Rock-drill.



' E. M. MACKIE LfP. P. DOYLE.'

ROCK DRILL.

APPLICATION rILnn rma. s, 1909.

Patented Dec. 9, 1913.

3 SHBETB-SHEET 1.

E. M. MACKIE & P. P. DOYLE.

Boex DRILL. l APPLICATION FILED PEB. 8, 1909y KSK E. M. MACKIE & P. F. DOYLB.

ROCK DRILL.

APPLICATION FILED rEB.8.19o9.

Patented Dec. 9, 1913.

3 SHEETS-SHEET 3.

I, WSN;

Inde/ f5, 6i@ 1A/4M..-

www

UNITED STATES PATENT OFFICE.

EDWIN M. MACKIE AND PERCIVAL F. DOYLE, OF FRANKLIN, PENNSYLVANIA, ASSIGNORS TO CHICAGO PNEUMATIC TOOL COMPANY, OF CHICAGO, ILLINOIS,

A CORPORATION OF NEW JERSEY.

ROCK-DRILL.

Specification of Letters Fatent.

Patented Dec. 9, 1913.

Application filed February 8, 1909. Serial No. 476,616.

To all whom t may concern Be it known that we, EDWIN M. Macina and PERcIvAL F. DorLn, both residing .at Franklin, Venango county, Pennsylvania, the former being a citizen of the United States and the latter a citizen of the Dominion of Canada, have invented certain new and useful Improvements in Rock- Drills, of which the following is a specification.

Our invention relates to rock drills and the obiect thereof is to provide therefor a continuous Water or air service or intermittent water and air service, such water or air or both together being discharged through the drill steel to thoroughly clean the latter' of all cuttings and the like, thereby increasing the cutting or drilling power by enabling the cutting end of the steel to strike on a clean surface at each blow and by enabling an easier rotation of such drill steel by the, consequent absence of mud in the hole.

The various features of advantage and utility in our construction of rock drill with said means embodied therein will be apparent from the description hereinafter given.

In the drawings, Figure I is a central longitudinal section of a rock drill embodying our invention; Fig. 2 a front end elevation thereof; Fig 3 an enlarged side elevation of the rifle bar nut; Fig. 4 an end elevation of such nut; Fig. 5 a central longitudinal section of a portion of the rock drill similar to Fig. 1 but on a larger scale; Fig. 6 a section on Ythe line GG of Fig. Figs. 7 and 8 sections on the lines 7**7 and S#8 respectively of Fig. 5; Fig. 9 a View of a modified form of construction as to one of the details; and Fig. 10 a view similar to Fig. 9 but show ing a part thereof on a larger scale.

Referring to the. present embodiment of our invention as illust rated in the drawings, the usual construction of rock drill is ein ployed but modified in the several respects hereinafter referred to. As to the rock drill construction, it will be sufficient to state that such drill comprises essentially a cylinder 1, piston head Q adapted to reciprocate therein and having a piston rod 3, the rifle or rot ating bar 4 received by the chamber 5 in thel rear end of the piston head, the rifle bar nut 6, thrust ring 7, ratchet ring 8 and a backhead 9. At its front end the piston 3 is suitably constructed to carry and hold a drill steel 10. As usual, the main valve 11V is operated by means of the rocker 12, which in turn is actuated by the piston head in its movements, the main valve controlling the admission and exhaust of fluid pressure to and from opposite ends of the piston chamber within the cylinder through the passages 13 and 14.

The rock drill as just described is of the usual and well known construction, but is modified for the incorporation of our improvements in the manner now to be explained. The piston rod 3 is provided with a central longitudinal fluid passage 3a which is adapted to communicate at its front end with a similar fluid passage 10a extending longitudinally through the drill steel to the cutting end thereof. In practice, the inner end of the drill steel is received by a socket at the front end of the piston rod and packed by means of packing 15 to prevent any leak-v age of fluid pressure from the passage 3 around the drill steel. The rifle bar is also provided with a central longitudinal passage 4 which is in axial alinement with the passage 3a. Within these passages 3a and 4 is arranged a stationary tube 16 secured in fixed position in suitable manner in the back head 9 and extending forwardly through the rifle bar and into the rear end portion of the passage 3a, which is suitably counter-bored to receive it. This tube is of a sufficient length so that it will always project into the piston rod passage 3a in whatever position ,auch rod may he in its reciprocations. In the present instance the rear end of the tube is held in position in a central opening in the back head by means of packing 17 comA pressed against the tube by the packing nut 1S. At the rear of the back head and by means of the end cap 15) is formed a fluid chal'nl'ier 20 which communicates with thc tube 1G and also with the fluid passage 21 in the hack head. which in turn communirates with the pipe 22 connected with any suitable source of water or both water and air. i

In the construction illustrated in Figs. 1 and 5 packing is provided between the. passage. 3 and the tube 1f?, such packing in the present instance consisting of the two cupped leather packings 23 and 24 which are held within 'a packing box 25 and seportions of the iackinffs a ainst the bottom ot' the outer socket otl the box, the inner socket being arranged to receive the main portion of the I packing Qi. This packing and its packing boX occupy the extreme front end of the rille bar chamber 5 .uid the same are held in such position by means of the bushing or sleeve 27 in such chamber, such bushing pressing againsty the rear tace of the packing box, as clearly indicated in Figs. l and 5. This sleeve is itself held in position by means of the rifle bar nut (3 screwing into the rear end of the piston head and by preference provided at the rear end with the angular' notches Gi Vt'or convenient application for tools for applying or removing such nuts, Figs. 3 and il. As shown, the two packings 23 and it are oppositely depressed so as to prevent the passage or leakage of tluid in either direction along the tube 1G.

in practice the continuous Water or air service, or a service of mixed water and air, is provided by vhe operator through the supply pipe which may be provided with suitable valve mechanism (not shown) for this purpose. The tluid thus admitted through the supply pipe passes through'the passage 2l in the back head to the chamber' 2t) and thence through the tube t6, and through the passages 3 and l0a to the front end ot the drill steel.

In order to provide for an intermittent supply ot water and air, only one cup leather packing 2S, instead ot the two packings 23 and 24, is employed, as shown -in the modification, Fig. 9. This packing is so arranged as to act a check valve permitting the pressure to pass or leak by itself and along the tube and thence through the passages to the drill steel. The pressure here referred to leaking past the packing 28 comes Jfrom the rear end of the cushioning space of the piston chamber, such space be ing indicated between the lines X Y. "hen the piston has closed the rear port. 13 of the pisten chamber, the fluid trapped therein will become conipressed by the further movements ot' such piston and such lluid thus compressed will pass or leak along the ritle har and into the chamberv 5, and will leak or )ass along the tube 16 and also past the single packing 28 in the manner already described. At the same time water is being admitted through the tube from the su ply pipe Q2, so that in the reciprocat-ions ofthe plston an intermittent supply otI water and air will be forced through the fluid passages to the front end of the drill steel, the paclcing Q8 acting as a cheek valve and preventin g the return ot' pressure backwardly along the sides of the tool.

'the construction and arrangement herenbet'ore described are such thaty no appret ahlc or detrimental back pressure is created in practice in the fluid supply passages, but it desired a check valve might be interposed at any suitable point, for instance in the supply passage as shown in the modification in Fig. t), wherein the check valve 29 is of the ball type. and spring-pressed. However, where the. working is in rock rich in mineral or sheet ore, or soil where there is a possibility of the hole in the drill steel becoming plugged up with cuttings notwithstanding the tlow ot llnid therethrough, it is preferable to omit the cheek valve in order to prevent accumulation of pressure in the rifle bar chamber which might eventually stop the machine or possibly burst the packings.

Although we have shown the check valve in connection with the form of construction in which the single cupped leather packing is employed, it will be understood that such cheek valve may be employed in the other form of construction hereinbefore first described.

We claim:

l. In a rock drill, the combination of the cylinder, piston and rifie bar of such a drill, both the piston and bar having longitudinal passages and the piston having a ritie bar chamber, a tube arranged in said passages and adapted to communicate with a source ot [luid under pressure, and means for pre venting back flow around the tube within the piston consisting of a removable box located at the front end of the rifle bar chamber and having an opening for said tube, and packing arranged within said box and around the tube said box and packing" being formed as a unit.

In a rock drill the combination of a cylinder, piston, and ritle bar, both the pi8- ton and rille bar having longitudinal passages and the piston having at riHe bar cham` ber, a tube, arranged in said passages and adapted to communicate with the source of fluid under pressure, packing means at the front end of the ritle bar chamber, means engaging the rear end of said packing means and holdin the same in position and means engaging t e piston head at the rear end and engaging said first named means to hold it firmly against the packing.

EDiVIN M. MACHU". PERCIVAL F. DOYLF. Witnesses:

Guion T. HorkiNs, J. B. WILLIAMS. 

